This circuit was found in a Popular Electronics from the 90s. It is based on components still common today and an optical coupler for the triac. The sensor is a thermistor.
This analog thermometer was obtained from an English documentation. The sensor is a common diode...
Found in a RE Experimenter Handbook from the 90s, this circuit is intended for the use of LEDs in...
This noise limiter for low intensity signals was found in a 73 magazine for radio amateurs from the...